Vapor electric device.



E. WEINTRAUB & A. E. HIBSOHMAN.

VAPOR ELECTRIC DEVICE.

APPLICATION FILED JAN. 3, 1914.

Patented Apr. 14, 19M.

1,U93,36&

, Witnesses v Inventors Ezechiel Weintraub, J HIen E.Hi

UNITED STATES 5mm ormcn.

nzncnmn wnmrnnun AND ALLEN n. EIBscnMA n', or LYNN, MASSACHUSETTS, nssrcnons TO GENERAL ELECTRIC COMPANY, A conroner'ron or NEW YORK.

VAPOR ELECTRIC DEVICE.

Patented Apr. 114, 191%.

Application filed January 3, 1914. Serial No 810,165.

To all whom it may. concern Be it known that we, EZECHIEL WEIN- "main; and ALLEN E. HIBSCHMAN, citizens The present invention relates to vapor electric devices, such as-mercury arc rect1-' fiers or lamps, and its object is to improve the starting of said devices.

As is now well known, a mercury arc rectifier comprises essentially an easily vaporizable electrode, commonly consisting of mercury, and one or more coacting anodes,

these electrodes being located in a highly exhausted envelop. The arcs between the cathode and the anodes are started by generating ionized vapor from the cathode material, the most common method being the striking of an auxiliary or side branch are.

In some cases, particularly when the anodes of the device are in separate chambers having one or more bonds, the rectifying arcs start with difliculty at lower voltages than those corresponding to full-load, even though these voltages are considerably higher than the voltage necessary to maintain an arc. Taking as an example the 220 volt rectifier, of the so-called constant potential type, having two anodes, it will be observed that the anode chambers are bent forward in such a manner that a sinuous path is provided for the arcs between the cathode and the respective anodes. The purpose of this construction is to reduce the tendency for arcing bet-ween the anodes when the device is in operation. When the vacuum is very good such a rectifier will also start when the load is low, say, even as low as 15 volts on the direct current side, or about 50 volts on the alternating current side, but in due course of operation such a rectifier is liable to deteriorate in vacuum until it becomes impossible to start the rectifying arcs at voltages much below those corresponding to full load. A similar difliculty occurs in the three-phase rectifier in which three coiiperating anodes are used. In accordance with our invention the starting of these devices is assisted by providing the envelop in the vicinity of each of the anodes with a conductive coatingv which is electrically connected to the anode.

In the accompanying drawings Figurel shows In perspective a mercury arc'rectifier provided with a conductive coating on the outer surface of the anode chambers, and Fig. 2 is a 'fragmental detail illustrating the preferred form of coating which provides an active dissipation of heat.

The vapor electric device shown in the drawing comprises as usual an envelop 1 which ordinarily consists of glass, but may consist of other v treous conducting; material such asquartz. The envelop has a cathode chamber 2, anode chambers 23 and 4E and a condensing chamber 5. The cathode 6, preferably consists of mercury, and the anodes 7 and 8 consist of carbon or a refractory metal. Current connections to the electrodes may be made in theusual manner by sealedin conductors connected to external metal caps 9. The side branch auxiliary or starting arc is produced by contact of the mercury cathode with the auxiliary anode 1O usually by shaking the tube when suitable current connections have been provided.

A conducting coating 11 is provided on the outside surface of the glass, in extremely intimate contact with the surface and extending preferably over the surface of the anode chamber to the bend. This construction should not be confused with the static protector shown for the anode chambers in Hayden patent #996,502. The static protector is particularly useful for rectifiers operating on very high voltage such, for e.\'- ample, as series lighting circuits. As shown in the illustration of the Hayden patent, the static protector is spaced away from the outer surface of the envelop. In low volta {1c rectifiers, the static protector has no useful function; no matter how close to the walls it may be placed and even when in direct contact with the walls, the effect on the starting' is negligible.

The necessity of extremely intimate contact between the conductor and the walls of the glass with elimination of any intervening air space is the main factor which makes our invention operative in low voltage rectifiers. On the other hand, this intimate contact between the conductive coating and the walls of the envelop is detrimental in or gold paint, but in order to provide a good dissipation of heat and thus preventsoftening of the glass it is preferable to apply a black coating which will more readily absorb and dissipate heat than a shiny metallic coating.

According to one embodiment of the invention, the anode arms are first painted with a suspension of finely divided carbon in a liquid mcnstruum such as a solution of sugar, glucose, or the like, which is preferably mixed with borax. .This arbon paint is applied in a very thin layer to the surface of the. anode arms up to the elbow by the use of an ordinary paint brush or in any other convenient manner. The carbon paint may also slightly extend over the metallic anode cap so as to make contact therewith. This paint when dried is heated, the temperature being gradually raised to about 300 to 400 C. \Vhen cooled the painted surface is buffed or rubbed until shiny and smooth in appearance. A layer thus applied is shown in somewhat exaggerated proportions at 12 in Fig'. 2, the glass wall being indicated at 13. This vblack layer is a good absorber of heat. A material of high electrical conductivity such as, a gold enamel or tin foil is then appliedover the carbon coating, as represented by layer 14. The con'nncrcial gold enamel known onthe market .as Sapolin may be used. It need not completely cover the carbon surface but may be painted in strips one-fourth inch in width running lengthwise of the anode arms. The metallic coating should preferably make contact with the anode caps as by applying it over the carbon coating on the cap when the metallic coating is perfectly dry. An outside coating 15 of carbon paint, similar to the coating 12, is finally applied which assists in dissipating the heat.

What we claim as new and desire to secure by Letters Patent of the United States, is

l. A vapor electric device comprising an envelop, acathode, an anode, and a conductive coating upon the surface of said envelop near said anode only and electrically connected to said anode.

2. mercury vapor rectifier comprising a nonconducting envelop, a mercury cathode, cooperating solid anodes located in separate arms of said envelop, and conducting coatings on said anode arms, connected electrically to the respective anodes.

3. A vapor electric device comprisin a vitreous envelop, an easily vaporiza ble cathode,"a solid anode, and a conductive coating upon the outside surface of the envelop surrounding the anode, and electrically connected to the anode.

4. A mercury vapor rectifier comprising a glass envelop, a mercury cathode, cooperating anodes, and a. conductive coating in intimate contact with the wall of said envelop near each of said anodes, said coatings being respectively each electrically connected to the anode surromuled thereby.

5. A vapor electric device comprising a nonconducting envelop provided with at least one side chamber having a bend, an anode in said side chamber, an easily vaporizablc cathode in the main envelop, and a conductive coating on the surface of said anode chainber electrically connected to the anode.

6. An alternating current mercury vapor device comprising a glass envelop having a plurality of bent side arms, solid anodes in said side arms, a cooperating mercury cathode, a conductive coating on said anode arms in the vicinity of the anodes, electrically connected to the anode, and means for striking a starting arc in said envelop.

7.:A vapor electric device comprising a nonconducting envelop, an easily. vaporizable cathode, an anode, and a conductive layer having a black. surface coating the outside surface of said envelop in the vicinity of the anode and electrically connected thereto.

In witness whereof, we have hereunto set our hands this twenty ninth day of Decem ber, 1913.

EZECHIEL W'EINTRAUB.

\ ALLEN F. HIBSCHMAN.

Witnesses:

Ronnirr SIIAND, Jenn A. MoM NUs, Jr.. 

